100 rows, ranks 1–100, required title + artist fields, and no duplicate identity keys.
DATA GOVERNANCE
Public market context is useful only when its provenance stays attached.
HitLytics normalizes supported public chart metadata into one schema, validates completeness, records source/freshness, and keeps those facts separate from audio measurements.
The Cloudflare edge layer can serve a recently verified complete response while it remains fresh.
If live public sources temporarily fail, only a previously validated complete snapshot inside the bounded stale window may be shown.
99 rows—or any duplicate/missing rank condition—does not satisfy the Top-100 completeness gate.
Current public source adapters
| Adapter | Role | Validation | Fallback behavior |
|---|---|---|---|
| Apple Music U.S. public feed | Primary public Top-100 metadata | 100 unique ranks required | Falls through on error/incomplete response |
| iTunes U.S. public feed | Secondary public Top-100 metadata | 100 unique ranks required | Used when primary is unavailable |
| HitLytics edge cache | Resilience layer | Stores only previously validated 100/100 payloads | Bounded freshness/staleness; never manufactures missing rows |
Rank is not audio.
Chart position, title, artist, genre metadata and release date are market facts. They are not spectral balance, loudness, dynamics, tempo or any other waveform feature. HitLytics does not infer missing acoustic features from chart rank.
Source dependency rule
No single public provider should be treated as an irreplaceable product dependency. The source-adapter layer exists so a provider can be disabled, replaced or reviewed without rewriting the analyzer.
Commercial-use review gate
Before expanding any third-party dataset into a material commercial dependency, the operator should document its permitted use, retained fields, review date, fallback source and removal procedure. Public visibility alone is not treated as a blanket license.